1. Field of the Invention
The present invention relates to a drug-releaser which can carry a medicine to a localized affected part of a living body to permit the medicine to stay there for a relatively long time, thereby causing the medical effect long on the localized part of the living body.
2. Description of the Prior Art
In case that a medicine is applied to inflammation or tumor, the curing effect will depend on how long it can stay at that localized affected area. Generally speaking, the living body has a tendency to purge a medicine as a foreign substance from the body in the possible shortest time. Just after putting a medicine in the living body, the circulating blood starts absorption of the medicine, and the medicine will be purged out of the living body after passing through the kidney or the liver.
In order to keep the curing effect long lasting, it is necessary to retain the medicine in the vicinity of affected area as long as possible to prevent the prompt purge of the medicine from the living body. In an attempt to meet such a need a variety of dosing methods and drug-releasing materials have been proposed and actually used.
As one example, a medicine is put in a selected blood vessel little by little at intervals, thereby keeping the concentration of medicine in the blood at a given constant value. As another example, a given volume of medicine contained in a liposome capsule is put in the living body through the mouth, and then the encapsulated medicine will be gradually absorbed in the intestinal wall while passing through the intestinal canals in ten-odd hours. These conventional dosing methods, however, cannot permit the medicine to stay in the vicinity of the affected areas of the living body, such as tumors, and therefore, the medicine cannot exercise its curing effect on the affected part to its maximum capability.
In view of the above, one object of the present invention is to provide a drug-releaser which is free from the defect of conventional dosing methods as described above, permitting the medicine to stay long enough to make full use of its curing effect on the affected area of the body.